Packaging enclosures, such as the plastic bag, are used to enclose items varying from foodstuffs to manufactured parts. The packaging enclosure typically includes a continuous surface made from a web of flexible material that defines an internal volume for holding the items. To insert the item into the packaging enclosure, an opening is disposed through the surface of the enclosure to the internal volume. Once the item is inserted, the opening may be sealed to enclose the item and prevent the item from unintentionally falling out. In some instances the enclosure may be sealed in an airtight manner to, for instance, keep foodstuffs fresh or prevent enclosed fluids from leaking. Common methods of sealing packaging enclosures include fastening strips, heat-sealing, and adhesives.
As will be appreciated, when inserting items into the enclosure, air or other gas from the surrounding environment is also likely to fill the internal volume. It may be desirable to evacuate the entrapped air to, for instance, preserve foodstuffs or reduce the overall volume of the packaging enclosure. To evacuate the air, often the surface of the enclosure is collapsed around or bunched up about the item thereby forcing the air back through the opening prior to sealing the enclosure. Bunching up the packaging enclosure may, however, distort the opening in a manner that makes sealing the enclosure difficult. Also, some air may re-enter the internal volume before sealing is accomplished.
To prevent these disadvantages, it is common to partially seal the opening of the enclosure prior to evacuating the entrapped air. The packaging enclosure is then collapsed about or bunched up about the item to vent the trapped air or gas through the remaining unsealed part of the opening. After evacuation, the remainder of the opening is sealed. It will be readily appreciated that partial sealing and evacuation methods are relatively complicated and certainly not conducive to achieving an efficient rate in enclosing numerous packaging enclosures. Accordingly, there is a need for simplifying the airtight sealing of packaging enclosures.